[flang][runtime] Handle end of internal output correctly (#84994)

At the end of an internal output statement, be sure to finish any
following control edit descriptors in the format (if any), and (for
output) advance to the next record. Return the right I/O error status
code if output overruns the buffer.

Author: klausler

flang/runtime/format-implementation.h

@@ -66,15 +66,6 @@ template <typename CONTEXT>
 int FormatControl<CONTEXT>::GetIntField(
     IoErrorHandler &handler, CharType firstCh, bool *hadError) {
   CharType ch{firstCh ? firstCh : PeekNext()};
-  if (ch != '-' && ch != '+' && (ch < '0' || ch > '9')) {
-    handler.SignalError(IostatErrorInFormat,
-        "Invalid FORMAT: integer expected at '%c'", static_cast<char>(ch));
-    if (hadError) {
-      *hadError = true;
-    }
-    return 0;
-  }
-  int result{0};
   bool negate{ch == '-'};
   if (negate || ch == '+') {
     if (firstCh) {
@@ -84,6 +75,15 @@ int FormatControl<CONTEXT>::GetIntField(
     }
     ch = PeekNext();
   }
+  if (ch < '0' || ch > '9') {
+    handler.SignalError(IostatErrorInFormat,
+        "Invalid FORMAT: integer expected at '%c'", static_cast<char>(ch));
+    if (hadError) {
+      *hadError = true;
+    }
+    return 0;
+  }
+  int result{0};
   while (ch >= '0' && ch <= '9') {
     constexpr int tenth{std::numeric_limits<int>::max() / 10};
     if (result > tenth ||
@@ -246,8 +246,15 @@ int FormatControl<CONTEXT>::CueUpNextDataEdit(Context &context, bool stop) {
       ch = GetNextChar(context);
     }
     if (ch == '-' || ch == '+' || (ch >= '0' && ch <= '9')) {
+      bool hadSign{ch == '-' || ch == '+'};
       repeat = GetIntField(context, ch);
       ch = GetNextChar(context);
+      if (hadSign && ch != 'p' && ch != 'P') {
+        ReportBadFormat(context,
+            "Invalid FORMAT: signed integer may appear only before 'P",
+            maybeReversionPoint);
+        return 0;
+      }
     } else if (ch == '*') {
       unlimited = true;
       ch = GetNextChar(context);
@@ -297,11 +304,11 @@ int FormatControl<CONTEXT>::CueUpNextDataEdit(Context &context, bool stop) {
       return 0;
     } else if (ch == ')') {
       if (height_ == 1) {
+        hitEnd_ = true;
         if (stop) {
           return 0; // end of FORMAT and no data items remain
         }
         context.AdvanceRecord(); // implied / before rightmost )
-        hitEnd_ = true;
       }
       auto restart{stack_[height_ - 1].start};
       if (format_[restart] == '(') {

flang/runtime/internal-unit.cpp

@@ -41,16 +41,6 @@ InternalDescriptorUnit<DIR>::InternalDescriptorUnit(
   endfileRecordNumber = d.Elements() + 1;
 }
 
-template <Direction DIR> void InternalDescriptorUnit<DIR>::EndIoStatement() {
-  if constexpr (DIR == Direction::Output) {
-    // Clear the remainder of the current record.
-    auto end{endfileRecordNumber.value_or(0)};
-    if (currentRecordNumber < end) {
-      BlankFillOutputRecord();
-    }
-  }
-}
-
 template <Direction DIR>
 bool InternalDescriptorUnit<DIR>::Emit(
     const char *data, std::size_t bytes, IoErrorHandler &handler) {
@@ -109,7 +99,11 @@ std::size_t InternalDescriptorUnit<DIR>::GetNextInputBytes(
 template <Direction DIR>
 bool InternalDescriptorUnit<DIR>::AdvanceRecord(IoErrorHandler &handler) {
   if (currentRecordNumber >= endfileRecordNumber.value_or(0)) {
-    handler.SignalEnd();
+    if constexpr (DIR == Direction::Input) {
+      handler.SignalEnd();
+    } else {
+      handler.SignalError(IostatInternalWriteOverrun);
+    }
     return false;
   }
   if constexpr (DIR == Direction::Output) {

flang/runtime/internal-unit.h

@@ -28,7 +28,6 @@ template <Direction DIR> class InternalDescriptorUnit : public ConnectionState {
       std::conditional_t<DIR == Direction::Input, const char *, char *>;
   InternalDescriptorUnit(Scalar, std::size_t chars, int kind);
   InternalDescriptorUnit(const Descriptor &, const Terminator &);
-  void EndIoStatement();
 
   bool Emit(const char *, std::size_t, IoErrorHandler &);
   std::size_t GetNextInputBytes(const char *&, IoErrorHandler &);

flang/runtime/io-stmt.cpp

@@ -119,9 +119,6 @@ template <Direction DIR> void InternalIoStatementState<DIR>::BackspaceRecord() {
 }
 
 template <Direction DIR> int InternalIoStatementState<DIR>::EndIoStatement() {
-  if constexpr (DIR == Direction::Output) {
-    unit_.EndIoStatement(); // fill
-  }
   auto result{IoStatementBase::EndIoStatement()};
   if (free_) {
     FreeMemory(this);
@@ -165,7 +162,8 @@ template <Direction DIR, typename CHAR>
 void InternalFormattedIoStatementState<DIR, CHAR>::CompleteOperation() {
   if (!this->completedOperation()) {
     if constexpr (DIR == Direction::Output) {
-      format_.Finish(*this); // ignore any remaining input positioning actions
+      format_.Finish(*this);
+      unit_.AdvanceRecord(*this);
     }
     IoStatementBase::CompleteOperation();
   }
@@ -189,8 +187,21 @@ InternalListIoStatementState<DIR>::InternalListIoStatementState(
     : InternalIoStatementState<DIR>{d, sourceFile, sourceLine},
       ioStatementState_{*this} {}
 
+template <Direction DIR>
+void InternalListIoStatementState<DIR>::CompleteOperation() {
+  if (!this->completedOperation()) {
+    if constexpr (DIR == Direction::Output) {
+      if (unit_.furthestPositionInRecord > 0) {
+        unit_.AdvanceRecord(*this);
+      }
+    }
+    IoStatementBase::CompleteOperation();
+  }
+}
+
 template <Direction DIR>
 int InternalListIoStatementState<DIR>::EndIoStatement() {
+  CompleteOperation();
   if constexpr (DIR == Direction::Input) {
     if (int status{ListDirectedStatementState<DIR>::EndIoStatement()};
         status != IostatOk) {

flang/runtime/io-stmt.h

@@ -403,6 +403,7 @@ class InternalListIoStatementState : public InternalIoStatementState<DIR>,
       const Descriptor &, const char *sourceFile = nullptr, int sourceLine = 0);
   IoStatementState &ioStatementState() { return ioStatementState_; }
   using ListDirectedStatementState<DIR>::GetNextDataEdit;
+  void CompleteOperation();
   int EndIoStatement();
 
 private: